Polishing machine for v jewels



June 13, 1944. V c BLANCII-ION 2,351,095

POLISHING MACHINE FOR "V" JEWELS Filed Jan. 11, 1943 2 Sheets-Sheet 1 2224 v a 41 z$;fi 19 1,10 34 23 25 1 5.; f2 1 3 /J a INVENTOR. 10mCflZa/zr/wn, BY

jaww WM:

giro/ME) June13, 1944. c. BLANCHON POLISHING MACHINE FOR "V" JEWELSFiled Jan. 11, 1945 2 Sheets-Sheet 2 n 0 d mu mm mm m a w Patented June13, 1944 POLISHING MACHINE FOR V JEWELS Louis C. Blanchon, New York, N.Y., assignor to Meyer'Koulish Co. Inc., New York, N. Y., a corporationof New York 1 Application January 11, 1943, Serial No. 471,996

' 10 Claims.

The invention relates to the art of polishing jewels and provides moreparticularly a machine for mechanically and automatically polishingV-shaped cavities in jewels.

The objects and advantages of this invention will appear from thedescription which follows accompanied by drawings showing for purelyillustrative purposes a preferred embodiment of the invention. It is tobe understood, however, that the description is not to be taken in a,limiting sense, the scope of the invention being defined in the appendedclaims.

In the drawings:

. Fig. 1 is a plan view of a preferred form of polishing machine anddrive therefor, some parts being shown in section;

Fig. 2 is an elevation of the polishing machine shown in Fig. 1;

Fig. 3 is a side view of an element Of the drive, a section being takenon line 3-3 of Fig. 1;

Fig. 4 is an enlarged sectional view of a V jewel;

Fig. 5 shows a bottom polishing tool andchuck therefor;

Fig. 6 is an end view of the tool shown in Fig. 5;

Fig. 7 is an end view of the chuck shown in Fig. 5;

' Fig. 8 shows a side polishin tool and chuck therefor;

Fig. 9 is an end view of the tool shown in Fig. 8;

Fig. 10a illustrates the operation of polishing the bottom of a. Vjewel; and

Fig. 10b illustrates the operation of polishing the sides of a V jewel.

In the following description and in the claims various details will beidentified by specific names for convenience, but the names are intendedto be as generic in their application as the art will permit.

Like reference characters denote like parts in the several figures ofthe drawings.

The V jewel I!) to be polished is held in a suitable mounting, such as acollet' chuck II, fitting into a tapered bore I2 of a floating workspindle I3. The spindle I3 is mounted for rotation and for axialdisplacement in bearings I4 and I5 of a suitable support or base I6which may be secured to a bench by screws [1.

The spindle I3 carries a belt pulley I8 secured thereto by a pin I9.Suitable means are provided for urging the spindle I3 in an axialdirection,

a helical spring being employed for this purpose in the illustratedexample. The spring 20 bears against a thrust plate 2i against which thespindle I3 rests and is adjustable in tension by a knurled screw 22 in asleeve 23. The sleeve 23 is screwed into the base at 24 and forms thebearing I5.

A tool spindle 25 is mounted for rotation in bearings 26 and 21 of asecond support or cradle 28. A pulley 29 is secured to the tool spindle25 by a. pin 3|]. The mounting of the tool spindle is preferably suchthat the spindle has no freedom in an axial direction, a shoulder 3| andspacers 32 and 33 being provided to locate the tool spindle 25relatively to its bearings 26 and 21.

The relative arrangement of the work spindle I3 and the tool spindle 25is such that the spindles are normally aligned. Means are provided fordisplacing one spindle parallel to its axis to produce a certaindesirable movement between the polishing tool and the jewel as will behereinafter explained in greater detail. For this purpose the cradle 28is pivotally mounted for rocking movement on a bar 34. The bar 34 has ashoulder at 35 and an end portion 36 of reduced diameter on which thecradle 23 rests on pivot bearings 31 and 38. A collar 39 secured to thereduced portion 36 by a pin 40 holds the cradle in place. A doublepulley M is mounted on the end portion 36 and drives the pulley 29 by abelt 42. The double pulley 4| is located relatively to the cradle byspacers 43 and 44. The bar 34 is adjustably held in the base I6 by handoperable screws 45 and 46 permitting of an adjustment in the distancebetween the work spindle and the tool spindle.

Means are provided for periodically displacing one spindle parallel toits axis during the polishing operation. That is to say, the spindle hasan oscillating movement transversely of its axis in its normal positionbut the axis of the spindle in any displaced position is parallel to theaxis of the spindle when in its normal position. In the illustratedexample an eccentric 41 imparts a rocking movement to the cradle 28through a rod 48. The rod is connected to a crank pin 49 of theeccentric with one end and is linked to the cradle with the other. Theconnection of the rod 48 with the cradle is conveniently made by meansof a bolt 50 having a forked end 5| to which the rod 48 is linked by apin 52. The bolt extends through the cradle 28 and carries a thumb nut53 bearing against one end of a helical spring 54. The other end of thespring 54 rests against the cradle. The bolt and spring arrangementpermits an additional parallel displacement of the tool spindle by handto facilitate the insertion of a tool, as will hereinafter appear. Itwill be understood that parallel displacement as herein used meansthe'spindle may be displaced transversely of its normal position butwhen displaced the axis of the spindle is parallel to its axis when innormal position The eccentric is preferably driven jointly with the workand tool spindles to coordinate the rocking the cradle with the rotationof the spindles. In the illustrated example, the eccentric 41 is mountedon a drive shaft 55 by a pin 56a. The drive shaft rests in bearings 51and 58, carries pulleys 59 and 60 for driving the pindles and a beltpulley 6| for connection to a prime mover or motor (not shown). A belt62 connects the pulleys 59 and I8 for driving the work spindle l3 in onedirection, and a crossed belt 63 connects the pulleys 60 and 4! fordriving the tool spindle 25 in the opposite direction.

The eccentric 41 is preferably adjustable to vary the amplitude of therocking movement of the cradle. Forthispurpose, one crank pin 49 may bemounted on a cross-head 64 adjustable in a guideway 65 by means of ascrew 66 (see Fig. 3). I

A V-jewel is shown in greatly enlarged section in Figure 4. The jewelconsists of a body l of sapphire, ruby or other suitable material andhas a V-shaped cavity produced by drilling or grinding. The cavitycomprises a curved bot tom portion '61 and a straight wall portion 68including an angle a.

The size and the angle a of the V-cawty vary according to the purposefor which the jewel is to be used. A much used jewel has a cavitymeasuring one millimeter in diameter measured across the face of thejewel and an angle a of 85 degrees. s I

Although the bottom and the wall portions 61 and 68 of the V cavity maybe polished in one operation by means of a single tool, it is preferredto employ separate tools for polishing the two portions, each tool beingdesigned for its particular purpose.

The polishing tools are preferably made of resilient non-metallicmaterial, such as fibre or wood, the latter being particularly wellsuited. Diamond'dust mixed with a lubricant serves as a polishingmedium.

A preferred form of bottom polishing tool and chuck or holder thereforare shown in Figures 5 to.7. The tool 69 consists of a piece of materialof elongated, preferably rectangular cross section, as shown in Fig. 6,and has sides which taper towards one end. A convenient length for thetool is approximately 60 millimeters. Commercially available toothpicksof the form shown, are admirably suited as polishing tools. The point Hof the tool is trimmedto the approximate angle or of the cavity to bepolished by means of a conventional cutting implement, such as a pair ofscissors or a side cutter used by instrument makers.

The tool is held in a suitable chuck preferably in such manner as toimpart a rotation to the tool while permitting the tool to tiltrelatively to the chuck at the point of engagement. A suitable chuck fortoothpicks is obtained by drilling an axial hole 12 into a center 13 andslotting the face of the cone I4 of the center to about one-half thedepth of the hole as shown at 15 in Figures 5 and '7, the incision beingat right angles to the axis of the center. The chuck thus obtained holdsflat toothpicks firmly for rotation and permits of considerable tilt atthe point of engagement' The chuck may be provided with a taper l6fitting in a. corresponding bore in the tool spindle 25.

A preferred form of side polishing tool is shown in Figures 8 and 9. Around piece 11 of suitable material such as wood is securely held in achuck 18 which may have an internal taper 19 for gripping the tool andan external taper 80 fitting into the tool spindle 25. The point 8| ofthe tool is accurately shaped to the angle a of the V-cavity to bepolished, which is conveniently done by grinding the point on anabrasive disc. A convenient length for the polishing tool 11 isapproximately 25 millimeters measured from the point H to the chuck 18.A commercially available round toothpick measuring about 2% millimetersin diameter is very well suited as a side polishing tool. Diamond dustmixed with a lubricant serves again as a polishing medium. It will benoted that in the illustrated mounting the tool 71 is relatively rigidbecause of its larger cross section and its shorter length as comparedto the bottom polishing tool 69, a preferred free length beingapproximately 25 millimeters measured from the point to the chuck. Thetool is held rigidly in the chuck 18, there being no freedom of tilt atthe point of engagement between the tool 11 and the chuck. v

The operation of the polishing device is as follows: After insertion ofa jewel [0 into the collet H the collet is placed into the taper l2 ofthe work spindle l3 causing the collet to close and hold the jewelfirmly. A polishing tool 69 or 11 is then inserted with its chuck 16 or18 in the tool spindle 25. For convenient insertion of the tool, thecradle 28 may be tilted by hand about its pivot 36 against the actioirofthe spring 54 causing the tool spindle 25't0 be brought out of alignmentwith the work spindle l3. The point of the tool to which a polishingagent has been applied is then placed in the cavity of the jewel I0which is facilitated by retracting thework spindle in its floatingmounting against the action of the spring 20. l

After the drive shaft 55 is set in m0ti0n,the work and tool spindles arerotated in 'opposite direction through the belts 62, 42 and 63. Inaddition, the cradle 28 is rocked about its pivotal axis by theeccentric 41, the proper amount of oscillation being determined by asuitable adjustment of the crank pin 49 and cross-head 64 in theeccentric. The rocking of the cradle 26 cause a change in the distancebetween the jewel and tool chuck which is compensated for by thefloating mounting of the work spindle l3 urged towards the tool spindleby the spring 20.

A suitable speed for polishing a jewel having a V-cavity of about onemillimeter diameter, measured across the face of the jewel, isapproximately 4000 R. P. M. for the work spindle l3, and 4000 R. P. M.for thetool spindle 25. The resulting total relative speed between thejewel and the tool is therefore approximately 8000 R. P. M. Theeccentric is preferably so driven as to make one complete revolution for25 revolutions of the tool spindle or revolutions of the jewelrelatively to the tool. i I

The polishing-action which takes place within the cavity of the jewelandthe minute movements of the points of the tools relatively to the cavityare about as follows:

The bottom grinding tool 69 is shown enlarged in Figure 10a in which thesize of the jewel is exaggerated to facilitate the illustration.

As hereinbefore set forth, the point of the bottom polishing tool 69 isof nearly uniform thickness 1(Eig. 6 sand is :shaped approximately -zto.the angle a :formed by the side walls ;f the 'V-ecavity. .A polishingmedium is ,appliedto the .point and the machine fis then set in motion..As ?the tool is rotated, the .point H of the tool undergoes a certainwear under thepressure'of "the .-spring '20,;it being :apparent that the"wear is the greatest "near the opening of the cavity at :"tance betweenthe jewel .10 and the chuck I3.

Asa result the tool is rapidly worn away at b and lb and bears primarilyagainst the bottom 61 of the cavity withritstipr ortion C, thus polish-;ing the same.

The relative motion between the tool and the .cavity is both rotary :andtranslatory. the .rotary movement being, of course, the rotationimparted to the tool by the .tool chuck 1.3, a translatory movement ebeing produced by the rocking of the cradle, causing the side portions band b .of the tool to bearagainst the edge of :the

cavity and forcing the .tip 0 over to thesurface near the bottomopposite the point of contact. In the position shown in heavy lines inFigure 100. the point of .thetool contacts the edge of the cavity near11 forcing the tip 0 below the center aline d-d. In the position'shownin broken lines the point of contact is near b forcing the tip 0 above-the center line 11-01. The result of the combined irotary and wobblingmovement is a :uniform polishing action at :the bottom portion of thecavity.

Referring now to movementof the tool 59 relatively to its chuck .I3it isapparent that the rocking of the cradle 28 by the amount E causes atilting e of the tool axis relatively to the spindle axis, the tip ofthe tool remaining practically on the axis d-d of the jewel, except forthe minute displacement e above referred to.

Referring now to the side polishing tool, it will be remembered that thetool H is of preferably circular cross section and rigidly mounted inits chuck 18. The point 8i of the tool is accurately ground to the anglea of the cavity. By reason of the rigid mounting of the tool ll, itslarger cross section and shorter length, the point 8| of the tool makesa translatory movement e which is approximately equal to the amplitudeof oscillation E of the chuck 13. During the polishing the point 8| ofthe tool H is displaced parallel to itself without tiltof the tool axisd-d rela- I tively to the jewel-axis, thus producing a most accuratepolishing movement maintaining the side walls of the cavity perfectlystraight.

During the polishing the tool ll makes a slight movement into and out ofthe cavity by an amount j which is taken up by the floating mounting ofthe work spindle l3 and its spring 20. This additional movement makesthe polishing action most effective in removing circular grooves in thecavity sometimes caused by the tool by which the cavity was ground.

It will be apparent from the foregoing that the present inventionprovides a machine by means of which large numbers of jewels may bepolished with utmost precision and uniformity never attainable byconventional hand polishing methods. The polishing time is extremelyshort and of the order of thirty seconds for either tool assuming thematerial of the jewels to be sapphire.

'si-Ve to produce, easy to set up and adjust and :simple to operate. Thenovel device may be op- .eratedby unskilled workers and willproduceresultswhich are vfar superior to the bestmanual performance ofhighly skilled jewel workers.

While certain novel features of the invention have been disclosedherein, and are pointed out in the annexed claims, it will be understoodthat various omissions, substitutions'and changes may .be made by thoseskilled inthe art without departing from the spirit :of the invention.

What isclaimedis:

l. A polishing :machinefor V cavities injewels comprising, incombination; a rotatable chuck for holdingthe jewel; a-spindle mountedfor r0- tation with its axis normally coaxial with said chuck withfreedom of oscillating movement about an axis parallel to the axis ofsaid chuck; means for rotating the chuck and said spindle in oppositedirections; and means including an oscillating support for the spindlefor periodically displacing said spindle to either side of the chuckaxis while maintaining the spindle axis parallel with the chuck axis.

.2. A polishing machine for V cavities in jewels comprising, incombination, a spindle mounted for rotation about its axis and fordisplacement to eitherside of its axis; a floating chuck for holding thejewel, the chuck being mounted for rotation substantially coaxially withthe normal position of said spindle and for axial displacement towards,and away from, said spindle;

means for urging the chuck towards said spindle; means for rotating saidchuck and said spindle in opposite directions; and means including apivoted spindle support for periodically displacing said spindle toeither side of the chuck axis while maintaining the axis of said spindleparallel to the chuck axis.

3. A polishing machine for V cavities in jewels comprising, incombination, a base; a first spindle mounted in said base for rotationabout its axis and for axial displacement; a spring urging said spindlein an axial direction; a chuck on said first spindle for holding ajewel; a bar mounted in said base parallel to said first spindle; acradle pivotally mounted on said bar for rocking movement; a secondspindle mounted in said cradle for rotation about its axis substantiallycoaxially with said first spindle; means carried by said second spindlefor holding a polishing tool; means for rotating said spindles inopposite directions; and means for periodically rocking said cradleabout said bar.

4. A polishing machine for V cavities in jewels comprising, incombination, abase; a first spindle mounted in said base for rotationabout its axis and for axial displacement; a spring urging said spindlein an axial direction; a chuck on said first spindle for holding ajewel; a bar extending through said base parallel to said first spindle;means for adjustably clamping said bar in said base; a cradle pivotallymounted on said bar for rocking movement; a second spindle mounted insaid cradle for rotation about its axis substantially coaxially withsaid first spindle; means carried by said second spindle for holding apolishing tool; means for rotating said spindles in opposite directions;and means for periodically rocking said cradle about said bar.

5. A polishing machine for V cavities in jewels comprising, incombination, a base; a first spindle mounted in said base forrotationabout its axis and for axial displacement; a spring urging said spindlein an axial direction; a chuck on said first spindle for holding ajewel; a bar mounted in said base parallel to said first spindle; acradle pivotally mounted on said bar for rocking movement; a secondspindle mounted in said cradle for rotation about its axis substantiallycoaxially with said first spindle; means carried by said second spindlefor holding a polishing tool; an eccentric including means for adjustingits eccentricity; meansfor driving said spindles in opposite directionsand fordriving said eccentric; and a rod hinged to said cradle andconnected to said eccentric for rocking said cradle.

' 6. A polishing machine for V cavities in jewels connecting said cradlewith said eccentric for rocking the cradle about its pivotal axis; andjoint means for driving said spindles in opposite directions and fordriving said eccentric.

7. In a polishing machine for V cavities in jewels the combination witha rotatable jewel chuck and a rotatable tool chuck; one of said chucksbeing periodically displaceable while at all times maintaining its axisparallel tothe axis of the other chuck, of a non-metallic bottompolishing tool held in the tool chuck for rotation therewith and withfreedom-of tilt relatively thereto, one point of the tool correspondingsubstantially to the shape of the V in the jewel v to be polished.

8. In a polishing machine for V cavities in jewels the combination witha rotatable jewel chuck and a rotatable tool chuck, one of said chucksbeing periodically displaceable while at all times maintaining its axisparallel to the axis of the other chuck, of a wooden bottom polishingtool held in the tool chuck for rotation therewith and with freedom oftilt relatively thereto, the point of the tool being of greaterwidth'than thickness and corresponding substantially to the shape of theV in the jewel to be polished.

9. In a polishing machine for V cavities in Jewels the combination witha rotatable jewel chuck and a rotatable tool-chuck, one of said chucksbeing periodically displaceable while at all times maintaining its axisparallel to the 'axis of the other chuck, of a non-metallic relativelyrigid side polishing tool held in the tool "chuck, the point of the toolbeing of circular'cross section and corresponding in shape to the Vinthejewel to be polished. r

10. In a polishing machine for V cavities in jewels the combination witha rotatable jewel chuck and a rotatable tool chuck, one of said chucksbeing periodically displaceable while at all times maintaining its axisparallel to the axis of the other chuck, of a wooden relatively rigidside polishing tool of substantially circular cross section held in thetool chuck, the point of the tool being shaped to correspond to the V inthe jewel to be polished.

LOUIS C. BLANCHON. i

